Mechanism for folding carton flaps



Dec. 13, 1955 P. E. FISCHER ETAL MECHANISM FOR FOLDING CARTON FLAPS 5 Sheets-Sheet 1 Filed Dec. 23, 1950 PAUL E. FISCHER ROBERT S. HEDIN CHARLES H. SWANSON HENRY E. WISSMAN BY M4441. ATTURIIEY 1955 P. E. FISCHER ETAL 2,726,498

MECHANISM FOR FOLDING CARTON FLAPS Filed Dec. 23, 1950 5 Sheets-Sheet 2 I HENRY E. WISSMAN GYM Arm/m P. E. FISCHER ET AL MECHANISM FOR FOLDING CARTON FLAPS Dec. 13, 1955 5 Sheets-Sheet 3 Filed Dec. 23, 1950 5 a y 0 ,0? j F/ WM m Dec. 13, 1955 P. E. FISCHER ET AL MECHANISM FOR FOLDING CARTON FLAPS 5 Sheets-Sheet 4 Filed Dec. 23, 1950 HENRY E. WISSMAN GYM; ATTDflI/EY um u. IQ

Dec. 13, 1955 P. E. FISCHER ETAL 2,726,498

MECHANISM FOR FOLDING CARTON FLAPS Filed Dec. 23, 1950 5 Sheets-Sheet 5 IN VE N TORS PAUL E. FISCHER ROBERT S. HEDIN CHARLES H. SWANSON HENRY E. WISSMAN BYdkw My "rm" United States Patent MECHANISM FOR FOLDING CARTON FLAPS Paul E. Fischer, Minneapolis, Robert S. Hedin, St. Paul,

Charles H. Swanson, Minneapolis, and Henry E. Wissman, St. Paul, Minn., assignors to General Mills, Inc., a corporation of Delaware Application December 23, 1950, Serial No. 206,463

25 Claims. (Cl. 53149) This invention relates to improvements in packaging machinery for folding closure flaps over the top of a carton.

The present application is a continuation-in-part of the patent application entitled Carton Closing Machine, Serial No. 206,464, filed December 23, 1950, by Fischer, Hedin, Swanson and Wi'ssman.

The carton upon which the mechanism of the present invention operates has received closing operations by a previous machine such as that shown by the abovementioned co-pending application. Previous operations have folded a front closure panel over the carton top and brought a rear closure panel over the carton top to overlie the front panel. The side closure panels which are attached to the front and rear panels are creased and folded to form doubled triangular lateral flaps. The carton is sealed by thermoplastic adhesive which is present on the face of the closure panels and in the previous operation has been heated to seal the overlapped front and rear closure panels and to laminate the double thickness flaps. The mechanism of the present invention functions to complete the closure of the previously sealed carton to form a neat compact package. To complete the closure, the flaps must be folded inwardly to overlie the sealed closure panels and the top cover flap brought over the folded side flaps.

In folding the side flaps inwardly over the top of the carton, stress is created at the fold line due to the sharp bending of the double-layered side flaps. This stress causes the layers of the side flaps to have a tendency to shift and forms an unstable fold as the closure tends to spring open. To relieve the stress, the present invention heats the thermoplastic laminating adhesive between the layers to allow the layers to shift with respect to each other. By the provision of an insulating plate positioned over the previously sealed closure panels, heat may be added to the folded side flaps without danger of the heat penetrating to the first closure and loosening the seal. The insulating plate is rigidly constructed so as to prevent the mechanical pressure required to fold the ears inwardly from creating pressure and damaging the seal. The present invention also provides a unique mechanism for folding the flaps which is especially adapted to high speed automatic packaging machinery operation.

After the flaps have been folded over the top of the carton and the stress is relieved by the addition of heat, the top closure flap is folded over the side flaps and the thus closed carton discharged from the machine to permit the adhesive to completely solidify.

An object of the present invention is to provide a machine which will successfully fold closure flaps over the top of a carton as a step in the closure of the carton.

A further object of the invention is to provide a device which will bend the outlying flaps of a carton about their lines of attachment to the carton, forming straight line folds to obtain precise, sharp carton edges and which will accurately position the flaps in closed position in ice their correct relation to the carton, accomplishing these functions rapidly to accommodate a continuous series of cartons and yet performing the folding gently in order to handle cartons formed of fragile and pliable material.

A further object of the invention is to provide a machine which will fold and seal carton flaps by the use of heat and pressure over the top of a carton which is sealed with thermoplastic adhesive and which is empty or filled with a non-solid substance which will give no backing when pressure is applied to the closure flaps.

Other objects and advantages will be apparent in the course of the following description and accompanying drawings in which:

Figure 1 is a perspective view of a carton top, illustrating the manner in which the carton is sealed before operation by the present invention;

Fig. 2 is a perspective view of a section of the turret showing a pre-sealed carton which is to be completed by the mechanism of the present invention;

Fig. 3 is a perspective view of the section of the turret showing a protective plate positioned over the carton top;

Fig. 4 is a sectional view taken along line 4-4 of Fig. 3;

Fig. 5 is a perspective view of the mechanism of the station for folding the flaps over the top of the carton;

Fig. 6 is a perspective view of a portion of the mechanism of Fig. 5, taken from a different position;

Fig. 7 is a perspective view of the mechanism of the flap folding station, having portions removed to show details of construction;

Fig. 8 is an enlarged fragmentary front elevation showing the side flaps being creased;

Fig. 9 is an enlarged fragmentary front elevation illustrating the flap being folded over the carton;

Fig. 10 is a front elevation showing the path of motion of the shoe as it folds the flap over the carton top;

Fig. 11 is a perspective view of the mechanism of the station for applying heat to the carton flaps;

Fig. 12 is an enlarged perspective view of the heating block;

Fig. 13 is a perspective view of the carton as it is positioned at the station for heating the flaps;

Fig. 14 is a fragmentary sectional view taken along line 14--14 of Fig. 13;

Fig. 15 is a fragmentary sectional view taken along line 15-15 of Fig. 13;

Fig. 16 is a perspective view illustrating the stationary folding members for holding the side flaps against the carton top and folding the cover flap over the side flaps; and

Fig. 17 is a perspective view of a mechanism of Fig. 16, taken from a different angle to more fully illustrate the action of the stationary folding members.

Referring to Fig. l, a carton of the type which may be closed by the mechanism embodying the preferred form of the invention is shown. The carton 16 has side walls 18 which extend above the plane of the carton top 20 to form closure panels. The carton is formed of multiple layers having an outer shell or covering and an inner liner This operation has doubled the side panels 28 upon themselves to form double thickness laterally extending ears 30. The carton liner material is coated on its outer face with a-thermoplastic adhesive and the covering material similarly coated on its inner face. The carton is formed of a soft, pliable material such as metallic foil. With the closure panels of the carton thus folded, heat and pressure have been added to laminate the facing surfaces and form a seal, the carton top being in the state illustrated in Fig. 2. All this has been previously completed by mechanism such as that shown in the application of which the present application is a continuation in part.

To complete the closure of the carton, the lateral cars 30 must be folded over the top of the carton and the cover flap 22 folded over the carton to overlie the ears. It will be seen, when the description of the machine becomes clear, that the machine may be utilized to close various types of cartons having lateral or front closure flaps, obtaining many of the advantages afforded by the present invention. The machine, however, is best adapted to solve the problems and overcome the difiiculties presented by a package sealed with thermoplastic adhesive and having the construction described above.

It will be observed that the teachings of the present invention could be utilized for operation on either end of a carton and the invention is not to be limited to closing the top end.

The carton is shown carried in a pocket 32 in a turret 34. The turret is rotatable about a central supporting post 36. Operating mechanism, not shown, is provided to index the turret to carry the carton through a series of top-folding stations, briefly halting the carton at each station while a folding operation is performed. Retaining rails 38 and 46 extend peripherally around the turret supported on vertical posts 42 mounted on a frame 44 to hold the carton in the pocket. A rail 43 extends around the turret and is also supported by the post 42 to hold the cover flap 22 in its horizontal out-of-the-way position. The turret shown is also illustrated in the co-pending application, Carton Closing Machine, Fischer, Hedin, Swanson, Wissman, and the mechanism embodying the present invention may be combined in the turret shown in the application. The present invention, however, is not to be limited to that use and may be used to close a carton previously handled by any suitable type machinery.

Referring to Figs. 2, 3 and 4, a flat protective plate 46 is shown suitably carried on a carrier plate 48. The carrier plate has radial sliding movement, and support bars 50 attached to the bottom of the plate 48 have pins 51 on the ends which ride in bearing slots in guide members 52 on the turret. Movement of the plate 48 in a radial direction slides the protective plate 46 over the top of the carton to position shown in Figs. 3 and 4. The plate slides in contact with the carton in the direction which the overlying rear panels 26 are folded as to not disturb the fold. The protective plate thus positioned acts as a mechanical protector, preventing any pressure caused by folding the side flaps inwardly from disturbing the sealed panels beneath the plate. The plate also serves the function of being a heat insulator, preventing the annealing heat added to the flaps from softening the sealed panels. These functions of the plate will be more easily seen in the later description of the mechanism.

To slide the plate, a bracket 54 is secured to the carrier plate and has a pin 56 extending across a slot 58 in the end of the bracket. This pin is cradled between the fingers 60 of the bifurcated end of a pivotal lever 62. To pivot the lever, a stub lever 64 is pivoted on the turret and connected to the pivotal lever by means of a push rod 66. The upper end of the stub lever has -a cam follower 68 which rides in a slot 70 in a stationary cam 72 which is mounted on the center post 36 of the turret. As the turret is rotated, the stub lever riding in the cam slot is given pivotal movement to operate the plates.

The turret, having the protective plate positioned over the top carton end, pivots the carton into a flap folding station opposite a tower 74 which functions to support the flap folding elements. The tower, Figs. and 6, is suitably mounted on the frame 44 and a cam shaft 76 is rotatably carried in pillow blocks 78, also mounted on the frame. The shaft is constantly rotated by power means, not shown, and'may be connected to shafts at other folding stations by means of the bevel gear 8%. Cam shaft 82, journaled in the base of the tower, is rotated by means of shaft 76 through bevel gears 84. A pivotal arm 86 is pivotally mounted on the tower and carries a follower 88 which engages a cam 90 on the cam shaft. An adjustable rod 92 connects between the end of the pivotal arm and a crank arm 94, which is secured to a cross shaft 96 carried in the tower.

Kicker fingers 98 are also secured to the shaft 96, and with pivotal movement they pass up into channels 100 in the turret to strike the bottom surface of fiat spring leaves 102 which lie against the upper surface of the turret on each side of the turret pocket 32. The upper retainer rail 38 and rail 43 are interrupted at this station to permit the fingers to pass into the sides of the turret.

The leaves are suitably secured to the turret at 104 in such a manner that they are held flat against the turret surface. The kicker fingers 98, striking the bottom surface of the leaf, raise the leaf to erect the side flap 30 of the carton, creasing it over the side edge 106 of the protective plate in the manner shown in Fig. 8. The side edge 106 is positioned substantially along the line of attachment of the flap to the carton and therefore the raising of the flap will form a straight crease at the flap base.

As the finger drops back through the channel out of the turret, the flexible spring leaf springs back against the turret top and the carton flap drops back to an inclined position, shown in the dotted line position of Fig. 9. In this position the toe 108 of the folding shoe 110 easily catches under the flap to force it inwardly over the top of the protective plate as the shoe moves from the dotted to the solid line position of Fig. 9.

To operate the folding shoes, the cam shaft 82 carries a sprocket 112 engaging a chain 114 which also runs over a sprocket 116 mounted on a shaft 118 extending through the front of the turret. The chain is tensioned by means of a sprocket carried on an arm 117 adjustably secured to a boss 119 on the turret. Shaft 118 carries a gear 129 which drives a gear 122 mounted on a shaft 124 which extends through to the front of the turret. The gear also rotates idler gear 126 which in turn rotates gears 128 and 130 mounted on shafts 132 and 134 which extend through to the front of the tower.

These through-shafts carry cranks on the inner face of the turret in the manner shown in detail in Figs. 6 and 7. Cranks 136 and 138, carried on upper shafts 124 and 132, are pinned to the upper end of shoe carrying mem bers 140 and 142 which have flap folding shoes 110 and 144 suitably secured to the lower ends. Shoe 110 is somewhat longer than shoe 144 to fold the flap engaged by it ahead of the other flap and is provided with a notch 146 which prevents it from interfering with the central raised portion 148 of the protective plate 46. Cranks 150 and 152, carried on the lower shafts 118 and 134, are pinned to sliding blocks 156 which slide in elongated slots 158 in the shoe carrying members. The lower cranks 152 and 154 are slightly angularly advanced and somewhat longer than the upper cranks in order that when constantly rotating with the same angular velocity they will give to the folding shoe the unique path of motion indicated by the arrows numbered 159 of Fig. 10.

The descent of this path of motion is advantageous in that it folds the ears down upon the top of the protective plate with a gentle sweeping stroke, preventing any distortion or wrinkling of the relatively soft metallic foil material. It will be noted that any downward pressure given the flaps by the base of the folding shoe will not be transmitted to the seal of the overlapped panels beneath the protective plate as the plate resists the vertical force.

The protective plate 46, shown in detail in Fig. 3, is given a raised central portion 148 which is designed to increase the plate strength without hampering its functions. The sides 160 of the raised portion are cut back diagonally to permit the triangularly shaped flaps to lie against the upper flat surfaces 162 of the plate. These fiat surfaces taper toward the outer edge 106 from a slight ly thicker flat center portion 164. The raised central portion forms a shoulder 165 which fixes the position of the ears when they lie on the upper surface of the plate.

It will be noticed, Fig. 9, that when the side flap is folded over the edge of the protective plate, the inner layer of material 166 is bent around a sharper radius than the outer layer of material 168, thus creating strains and stresses both in the carton material and in the laminating adhesive. These stresses cause an unstable fold as when the downward pressure on the flaps is relieved they tend to spring upwardly to relieve the stress. In order to correct this condition and to reseal any possible leaks which may have occurred, due to crumbling of the adhesive along the edge of the carton, the present invention contemplates the re-melting of the thermoplastic adhesive. This will permit the layers of material to shift with respect to each other to relieve stresses and will result in sealing leaks which may have occurred in the sharp fold. The addition of this heat performs an annealing process on the carton relieving the stresses and strains to form a stronger closure. In this addition of heat the protective plate performs the function of acting as an insulator to prevent any heat applied to the flaps from reaching the sealed overlapping panels and loosening the seal there formed.

The turret then carries the carton to an annealing station opposite a tower 170 which is mounted on the frame 44 adjacent the turret (Fig. 11). A cam shaft 172 is rotatably carried at the base of the tower in pillow blocks 174 mounted on the frame, and the shaft is connected to the other shafts by means of a bevel gear 176, to be constantly rotated. A rocker arm 178 is pivotally mounted in the base of the tower and carries a follower 180 which rides against a cam 182 carried on the cam shaft 172. A tension spring 184 connected between the rocker arm and a bracket 186 secured to the tower rocks the arm as the cam rotates. A second rocker arm 188 is pivotally mounted at the top of the tower, and the outer ends of the rocker arms are connected by an adjustable connecting rod 190.

The inner end of the rocker arm 188 is connected to a cross head 192 carried for vertical reciprocation on a pair of guide bars 194. A pin 196 is mounted across a channel 198 in the cross head and extends through an elongated slot 200 in the rocker arm. A rod 202 extending from the lower side of the cross head is suitably secured to a heated block 204. The lower face of the block, shown in detail in Fig. 12, has raised portions 205 to correspond to the shape of the triangular flaps 30. Thus, when the block is pressed against the folded ears, heat will be transmitted only to the ears, and the block will not directly contact the protective plate 46.

The heater block is supplied with electricity through a lead 206 between the block and a connector box 208 carried on the cross head. A lead 210 from the connector box is connected to a suitable source of electricity. In operation, the rocker arm 144 lowers the block upon the top of the carton and holds it in contact with the ears for a sufficient length of time for the thermoplastic ad- 1 hesive to be softened. The protective plate 46 supports the ears and prevents any pressure from reaching the underlying sealed panels and also prevents the seal from being softened by heat. The excess heat is assimilated by the cooled plate which does not reach the temperature at which the wax becomes soft. The heat in the plate is dissipated at a later time when the carton has been discharged from the turret and the plate has been withdrawn from the top of the carton. A certain amount of heat is conducted away through the metal supporting plate 48. The protective insulating plate 46 could be constructed of an insulating material, but metal is more desirable because of the added properties of strength. The position of the insulating protective plate with respect to the flaps and heater block is shown in detail in Figs. 14 and 15.

When the thermoplastic has become softened, the heater head is lifted and the carton carried by the turret to the discharge station, as shown in Figs. 11 and 12. While the carton is being transported to the discharge station, stationary folding rails hold the flaps down against the top of the carton and the cover flap is folded over the carton flap.

A sloping rail 212 cams the flaps down against the top of the carton, as shown in Fig. 16. A heater element 214 supports the rail and keeps it warm to prevent wax from collecting thereon which would interrupt the smooth sliding passage of the carton flaps beneath the rail. The heating element 214, supported by a rod 216 clamped-in a supporting holder 218, is carried on the vertical post 42. Leads 220 supply electricity to the heater element.

As the carton is carried toward the ejecting station, the cover flap 22 is cammed up over the top of the side flaps by a curved rail 222, as shown in Fig. 12. The flap is folded over the front edge 223 of the protective plate which forms a sharp even crease.

The turret stops as the carton is positioned opposite the discharge platform 224. At that point the movable rear wall 226 of the carton pocket moves radially outward to eject the carton from the turret.

The ejector plate 226 forming the rear wall of the carton, as illustrated in detail in Fig. 4, is carried on a push rod 227 slidably journaled in the turret. The rod is reciprocated by a lever 228 pivotally mounted on a bracket 230 on the turret. A follower roller 232 on the end of the lever is engaged by a rotating cam 234 (partially shown) to pivot the lever and move the ejector plate radially outward. A tension spring 236 between the turret and lever returns the plate to its normal position in the turret pocket. The top cover flap is smoothed as it is ejected and slides beneath the blade 238 and the fiaps are held down tightly upon the top of the carton as the carton moves out beneath pressure plate 240. The blade and pressure plate are carried on a frame member 242, the blade being supported by a thumb screw 244 which threads into a lug 246 on the rear side of the blade and permits adjustment of the elevation of the blade. The plate is supported by pins 248 which extend through holes in the frame member 242 and compression springs 250 surround the pins and press the plate down upon the top of the carton.

The method shown herein, which includes folding the laminated flaps over the carton top and relieving the stresses by the addition of annealing heat, presents a stable, efiicient fold and is disclosed in the co-pending application Method and Mechanism for Folding Carton Flaps, Serial No. 202,518, filed December 23, 1950, now Patent No. 2,677,220.

The present invention has thus provided an improved mechanism for folding flaps over the top of a carton. The optimum has been achieved in an efficient fold as the stresses in the laminated material have been relieved by the addition of heat. The operation of the elements of the present invention are especially well adapted for use in a high-speed automatic type package machine Where all folding functions must be gentle to avoid damaging the material and yet speedy to achieve a high rate of performance.

The carton has received a smooth completed fold with the cover flap folded loosely over the side flaps. The flaps are held down tightly to the top of the carton while the adhesive, softened by the annealing heat, has time to solidify. The flap may then be sealed over the carton top to complete the closure by means of suitable machinery, preferably that of the type shown in the copending application entitled Method and Apparatus for Sealing Cartons, Serial No. 206,461, filed December 23, 1950, now Patent No. 2,696,245, Fischer.

While the invention is susceptible of various modifications and alternative constructions, we have shown in the drawings and have described in detail the preferred embodiment. However, it is to be understood that we do not thereby'intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

We claim as our invention:

1. A machine for folding the closure flaps of a carton having previously closed and sealed overlying closure elements, comprising means for supporting the carton, a protective plate movable over the top of the carton and having a relieved area the size and shape of the carton flaps and substantially the depth of the carton flaps so that a folding means may be moved over the flaps and plate without striking the shoulder formed by the relieved area, means to move the plate over the carton top, and means to fold the flaps inward to overlie the relieved portion of the plate.

2. A machine for folding the closure flaps of a carton having closed and sealed overlying closure elements, comprising a supporting and insulating plate to overlie the sealed closure elements and to have the flaps folded thereover, the area of the plate which is to be occupied by the flaps tapered outwardly to thin side edges, the area not to be occupied by the flaps raised to provide a shoulder to limit the position of the ears, means to position the plate over the end of the carton between the flaps, and means to fold the flaps over the plate.

3. A machine for folding the top closure flaps of a carton comprising a supporting plate positioned over the carton top, the edges of the plate being substantially coincident with the lines of attachment of the flaps to the carton, flat lifter members lying beneath the flaps, means to move said members upwardly to move the flaps to vertical position. and means to fold the flaps inwardly over the top of the plate creasing the flaps over said plate edges.

4. A machine for folding the top closure flaps attached to the top of a carton comprising means for supporting a carton, means movable over top of the carton providing a creasing edge positioned at the base of the flaps, means to move said creasing edge providing means over the carton, a pair of lifting surfaces each positioned beneath a carton flap, and means for elevating the surfaces to crease the flaps along their lines of attachment to the side walls.

5. A machine for folding the top closure flaps of a carton comprising a carrier for supporting the carton,

resilient members being fixed at one end and having fiat surfaces underlying the flaps, and means engageable with the underside of each of said fiat surfaces to move them upwardly and move the flaps to erect position.

6. A machine for folding the top closure flaps of a carton comprising a carton carrier having a pocket therein for supporting the carton, resiliently mounted flat-surfaced members positioned adjacent the pocket to underlie the carton flaps, passageways formed in said carrier member leading to the underside of said surfaced members, erecting members movable through said passageways to engage the underside of said surfaced members moving them to erect the carton flaps, and means for operating said erecting members.

7. A machine for folding the top closure ears of a carton comprising a carton carrier having a holder therein for supporting the carton, a protective plate mounted on the carrier having dimensions substantially equal to the carton end, means to slide the plate over the carton end, resilient fiat supports mounted on the carrier to lie beneath the carton ears, and means to lift the flap supports to bend the ears to vertical position over the sides of the protective plate.

8. A machine for folding carton flaps over the end of a carton comprising means for supporting a carton, folding shoes for forcing the flaps over the carton end,

and means for actuating the shoes from normal position in an arcuate path convex downwardly toward the carton to force the flap down upon the carton top and for actuating the shoes in substantially a straight line path to return to normal position.

9. A machine for folding carton flaps over the end of a carton comprising means for transporting a series of cartons past a folding station, folding shoes operatively positioned at the folding station, and means for actuating the shoes in an arcuate path convex downwardly from a position of non-interference with the cartons to a flap engaging and folding position and for actuating the shoes in a straight line path to return them to said noninterference position when the flaps have been folded.

10. A mechanism for folding flaps over the end of a carton comprising in combination means for supporting a carton, folding shoes for engaging the folding flaps and folding them over the carton, and operating means for the shoes comprising a pair of rotatable crank arms for the folding shoes operatively connected to the shoes and rotatable to operate same and move the shoes in a continuous oval shaped path to fold the carton fiaps over the end of the carton.

11. A mechanism for folding carton flaps over the end of a carton comprising a pair of flap folding elements, means for supporting the cartons in folding position relative to said elements, and a pair of rotatable crank arms operatively attached to each flap folding element to actuate the element through a path to fold the flaps over the carton end, one crank arm being angularly advanced with respect to the other crank.

12. A mechanism for folding carton flaps over the end of a carton comprising means for supporting a series of cartons and moving them individually into a folding station, a pair of folding shoes for engaging the flaps and folding them over the end of a carton, and a pair of constantly rotating cranks for operatively supporting and actuating the shoes, one crank being shorter than the other to give the shoes an elliptical path of action in the folding stroke and a direct return.

13. A mechanism for folding flaps over the end of a carton comprising means for supporting containers at a flap folding station, flap folding shoes, supporting arms for the shoes, a rotatable crank pinned to each arm, a second rotatable crank slidably connected to each arm, and means for simultaneously rotating the cranks.

14. A mechanism for folding flaps over the end of a carton comprising a carton carrier having a carton supporting pocket therein, flap erecting members positioned beside the carton and mounted on the carrier with their upper surfaces normally positioned in the plane of the carton end to form a support for the flaps, means for lifting said erecting members from their normal position to lift the flaps to a position projecting beyond the end of the carton, and flap folding shoes movable in an arcuate folding path to engage the carton flaps and force the flaps over the top of the carton.

15. A mechanism for folding flaps over the end of a carton comprising a fiat plate positioned over the end of a carton, with plate edges situated along the line of attachment of the flaps to the carton, carton folding shoes, means to lift the flaps above the plane of the carton top so that they may be engaged by the shoes, the plate edges creasing the edges of the flaps, and a pair of rotatable crank arms operatively connected to the folding shoes to move them through an arcuate path against the plate to crease and fold the carton flaps over the end of the carton.

16. A mechanism for folding flaps over the end of a carton comprising means to support the carton, a plate positionable over the end of a carton, flap erecting members situated at the carton sides facing the carton flaps, means for moving said erecting members past the end of the carton to extend the flaps beyond the end of the carton, a pair of folding shoes having lateral movement with respect to the carton to engage the flaps folding them over the end of the carton and having movement toward the carton to fold the flaps against said plate.

17. A mechanism for folding flaps over the end of a carton comprising a flat plate movable over the end of the carton with edges substantially coincident with the line of attachment of the carton flaps to the carton, erecting members positioned adjacent the carton side walls facing the carton end flaps, means for actuating the erecting members to move the flaps beyond the end of the carton and crease the flaps against the edges of the plate, and folding shoes movable laterally over the plate to complete the folding of the flaps over the carton end.

18. A mechanism for folding flaps over the end of a carton comprising means for supporting the carton, plate positioned over the carton end, a support for the plate, a raised portion on the plate to enhance the strength of the plate, a flat folding shoe, and means to actuate the shoe moving it against the plate to engage a flap and force it against the plate, a portion of the shoe being removed to prevent interference with said raised portion of the plate.

19. A mechanism for folding flaps formed of laminated material including thermoplastic adhesive comprising means for supporting the carton, means for folding the flaps over the carton end, a heated member for heating the flaps, having raised portions the shape of the flaps, and means moving the heated member against the carton end to engage only the laminated flaps.

20. A mechanism for folding flaps over the end of a carton comprising means for supporting the carton, a plate, means to position the plate over the end of the carton, means to fold the flaps over the top of the plate, a heated block having a raised face the shape of the carton flaps, and means moving the block to engagement with the folded carton flaps.

21. A mechanism for folding flaps over the end of a carton comprising a protective plate, means to position the plate over the end of the carton, means secured to the plate having heat-conducting properties for conducting heat away from the plate, means to fold the flaps over the plate, a heated block having a face with a relieved configuration to contact only the flap surfaces, and means to move the block into engagement with the flaps.

22. A mechanism for folding flaps formed of material laminated with thermoplastic adhesive over the end of a carton having sealed closure panels comprising a protective plate, means to position the plate over the carton end, means to fold the carton flaps over the top of the carton, a heated block having a raised surface corresponding to the size and shape of the flaps, and means to force the block against the folded flaps to soften the laminating thermoplastic, the plate preventing the block from pressing against the sealed closure panels and insulating the heat from the panels.

23. A mechanism closing a carton having sealed overlying closure panels, side closure fiaps attached to the panels are formed of laminations of material and thermoplastic adhesive, and a remaining closure flap, comprising a protective plate substantially the size of the carton end, means to position the plate over the sealed panels, means to force the side flaps upwardly creasing them against the plate edge, means to fold the flaps over the top of the plate, a heated block, means for moving the block against the flaps pressing them against the plate and softening the thermoplastic adhesive, means for folding the remaining flap over the side flaps, means for removing the plate from beneath said flaps, and means for holding the flaps in folded position while the heated side flaps cool.

24. A mechanism for closing a carton having sealed' overlying closure panels, side closure flaps attached to the panels and a remaining closure flap, comprising a protective plate substantially the size of the carton end, means to position the plate over the sealed panels, means to force the flaps upwardly creasing them against the plate edge, means to fold the flaps over the top of the plate, a heated block having a face shaped to contact only the carton flaps, means to force the block against the flaps, the plate insulating the heat of the block from the sealed panels, means for folding the remaining flap over the carton, and means for removing the plate from the carton end.

25. A mechanism closing a carton having sealed overlying closure panels, side closure flaps attached to the panels are formed of laminations of material and thermoplastic adhesive, and a remaining closure flap, comprising a protective plate substantially the size of the carton end, means to position the plate over the sealed panels, means to force the side flaps upwardlycreasing them against the plate edge, means to fold the flaps over the top of the plate, a heated block, means for moving the block against the flaps pressing them against the plate and softening the thermoplastic adhesive, means for holding the flaps against the plate, means for folding the remaining flap over the side flaps, and means for holding said flaps in folded position while the adhesive cools.

References Cited in the file of this patent UNITED STATES PATENTS 1,275,756 Rose Aug. 13, 1918 1,965,897 Lurgens et a1. July 10, 1934 2,246,243 Clark June 17,1941 2,550,516 Back Apr. 24, 1951 FOREIGN PATENTS 150,366 Austria Aug. 10, 1937 

